For the heating of blast furnaces, burners in power stations and similar apparatus, ground solid fuel, in particular coal, is increasingly used as fuel. This affords the advantage that, as compared with the combustible material conventionally used, such as coke, or even oil, a marked saving in terms of operating costs becomes possible. In order to allow uniform supply of the ground fuel into the furnace, a multiplicity of nozzle lances are usually arranged around the furnace. The ground fuel is supplied to them via individual lines (“lance lines”). In order to distribute the ground fuel, supplied by a grinding device, such as a coal mill, or an interposed conveying device, to the individual lines leading to the lances, a fuel distributor is provided. This has a chamber, to which the ground fuel is supplied via a connection. A multiplicity of individual lines lead from the chamber to the respective lances. One difficulty of this is that, in practice, an uneven distribution of the ground fuel to the individual lines often occurs, with the result that different quantities are supplied to the individual lances. This leads to different combustion and consequently to uneven heating of the individual fuel nozzles, this being undesirable.
In order to achieve an equalization and regulation of the supply to the individual lances, a coal distributor became known which has individual quantity controls on the individual lines leading to the lances (SU-A-1717640). One disadvantage of the solution is that it becomes increasingly more complicated with a rising number of lines, and, moreover, an only inadequate result is often achieved in spite of the considerable outlay. This applies particularly when the ground coal is supplied to the coal distributor over a relatively long delivery distance.
In another approach, a coal distributor is provided which has a pressure vessel with a chamber arranged below it (DE-C-3603078). In this case, the chamber is divided into a plurality of subchambers separated from one another, in each case one of the lance lines being connected to each subchamber. Further, a bottom connection for the supply of carrier gas is provided on each subchamber. However, distribution to the subchambers cannot achieve a sufficient equalization of the feed streams in the lance lines, and therefore individual controls on the lance lines have to be adopted in order to compensate quantitative differences. This is complicated.